Cone Beam Uses and Its X-ray Safety Compared
by Leo Cashman

At DAMS we are asked sometimes about the safety and the health risks in dentistry, and for many years we have assured our callers that routine dental x-rays provide the lowest dose of x-ray exposure of any diagnostic-rays used in health care. While all x-ray exposures inflict some harm to us at the cellular level, our cells have some ability to repair the damage, as with the use of vitamin C, selenium, glutathione and other anti-oxidants we normally have. Now dentistry has seen the emergence of the “cone beam” x-ray scanner, sometimes called the “cone beam CT scan,” which, like the CT scan used in medicine, gives a 3-dimensional view of the patient’s dental area, from one corner of the mouth to another. The dentist examining a cone beam scan can flip through different slices of the dental region and look for pathologies, problems and abnormalities that might occur in any area. While the x-ray exposure from a cone beam is perhaps 60 times higher than that of a panorex x-ray, it is still far less than the x-ray exposure of a medical CT (CAT) scan that is used a great deal in medicine.

Let us compare the different kinds of diagnostic x-rays and their typical x-ray exposure doses. The unit of exposure that we will use is the millisievert, abbreviated mSv, which is a scale for expressing the harmful impact of the dose, with higher levels indicating greater harm or addition to the cumulative risk of harm.

Medical x-rays: CT scan, typically 10 mSv, Chest x-ray 0.1 mSv, mammogram 0.4 mSv

Dental x-rays: cone beam, typically .060 mSv, but ranging from .068 to 0.599 mSv depending on the model of machine used; Panorex (panoramic view of entire mouth) .010 mSv typically; and a dental x-ray of a single tooth (peri-apical) or a bitewing x-ray .005 mSv

Everyday life exposures: due to cosmic rays from the stars, and due to natural radioactivity of materials in the air and ground and such as are found in our buildings that we live in, we have: background radiation for a year, on average, 2 mSv; from background radiation per day for an average day, .010 mSv; flying across the USA in a plane, 7000 miles, .020 mSv

From the above, we can see that the dose from a cone beam, while it gives six times as much radiation as a panorex and 12 times as much as a simple bitewing or PA x-ray, it is still pretty low in the larger picture. Its exposure is the same as what we get from six days of living on the Earth, and smaller by a factor of 33 than what we pick up from living on the Earth for a year. The cone beam is a dental adaptation of the CT scan used in medicine, but it gives off a far smaller dose, by a factor of 170, than the medical CT scan does.

A reasonable conclusion is that dental patients should not hesitate to use x-rays when undergoing a routine checkup as part of a more thorough exam every few years. They should not protest the x-rays that are normally needed when starting with a new dentist and also when there is suspicion of problems that cannot be completely understood from the dentist’s visual examination and probing. X-rays can help uncover such problems as tooth decay, abscesses, causes of pain, the extent of periodontal/gum disease around the teeth and impacts upon the jawbone, impacted teeth, TMJ problems and airway obstruction. X-rays are essential to dental practice and patient should expect that diagnostic x-rays will be requested by any holistic dentist from time to time.

This article was written by Leo Cashman and published in the March 2018 Issue of DAMS Dental Truth newsletter. For more information about DAMS, visit their website at www.amalgam.org